window.onload = function(){
const mainPage = document.getElementByld('mainPage');
const categoryPage = document.getElementByld('categoryPage');
const themePage = document.getElementById('themePage');
const minePage = document.getElementByld('minePage');
const pageList = mainPage, categoryPage, themePage, minePage]
const mainItem = document.getElementByld('mainItem');const categoryltem = document.getElementByld('categoryItem');
const thememltem - document.getElementByld('thememltem');
const mineItem = document.getElementByld('mineItem');


showPage (pageList, minePage)

mainltem.onclick = function(){
	showPage (pageList, mainPage)
}
categoryItem.onclick = function(){
	showPage (pageList, categoryPage)
	}
thememltem.onclick = function(){
	showPage (pageList, themePage)
}
mineItem. onclick = function(){
	showPage (pageList, minePage)
}

function showPage (pageList, showPage) {
	pageList. forEach(item => {
		
	item.style.display = 'none'
	})
	showPage.style.display = 'block'
}